I gained12 kg in a year and now i want to reduce it i avoid taking more food still it's not getting control what shall i do ? i can't do excercise

Go online: There are a number of online sites that will help you. You can put in your current weight, the amount of exercise that you are doing--or not doing. It will then help you determine the number of calories that you should be consuming to deduce your wt. This is an example of one of the sites: http://www.caloriecount.com/tools/calories-goal